二维平纹机织复合材料弹性性能预测的域分解方法

摘要

The domain decomposition method was proposed for the study of mechanical properties of 2D woven fabric composite (WFC) based on mesh superposition method. The domain decomposition method was different from traditional represent volume element method. Instead of modeling the fibre and matrix explicitly in traditional represent volume element method, domain decomposition method separately models the global domain and fibre domain, which can be easily discretized using the traditional solid element. Global domain was superimposed by fiber domain and matrix domain. The two domains were superimposed by coupling with multi- point constraints from commercial finite element package MSC. Nastran. The displacement function was established to simulate coupling between fibre domain and global domain by multi-point constraints. Domain decomposition method is easier to set up models of WFC than traditional represent volume element method. Numerical simulations show that the results predicted by domain decomposition method correlate very well with the experimental data. Otherwise, the tendency of mechanical properties under different fiber volume fraction of WFC was also investigated. With the increasing of fiber volume fraction, the moduli of WFC increases, while Poisson~s ratios decreases.%为了预测二维平纹机织复合材料的弹性性能，提出了基于有限元重合网格法的域分解方法。域分解方法与传统代表体元法的有限元建模不同，前者不再建立精细的纤维与基体模型，而是分别建立二维平纹机织复合材料单胞的整体域与纤维域，整体域是真实基体体积与纤维体积的叠加，两区域网格独立剖分，互不影响。采用MSC．Nastran中的多节点约束在纤维节点与基体节点之间建立位移协调来模拟纤维和基体单元的位移函数关系，实现了纤维域和基体域的耦合计算。研究表明，域分解方法大大简化了机织复合材料细观力学建模的复杂性，降低了建模时间，采用域分解方法预测的二维平纹机织复合材料弹性常数与试验值吻合较好，充分说明了该预测模型与方法的正确性。研究了不同纤维体积分数下，域分解方法预测二维平纹机织复合材料的弹性常数的变化趋势，结果表明，随纤维体积分数增加，模量呈上升趋势，泊松比呈降低趋势。